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To: "Rob Atkinson" <>, <>
Subject: Re: [TowerTalk] BLACKENED BRAID?,
From: "K0DAN" <>
Date: Tue, 14 Jun 2011 12:38:00 -0500
List-post: <">>
Hi Rob...

I am coming to the same conclusion. The black braid RG213 I have is probably 
shot, no matter what the reason. Fortunately is a relatively short run. My 
application is < 7 Mhz, loss not an issue, but I do run QRO. Not sure what I 
will replace it with (I have some NOS "good" cable in inventory) but need to 
assess pros/cons.

I agree with you completely about 1/2" LDF...I have 3 runs of 130' from the 
shack to the tower, buried 15 years, and never a hiccup from any. When I 
have used flexible cable (buried runs, rotor jumpers, dipole hangers, etc.) 
I ALWAYS have had some kind of electrical or mechanical (now chemical) 
problem! Of course hardline can't be used everywhere, but it sure is a 
low-maintenance product compared to the flexible stuff.

Thanks for your comments.


----- Original Message ----- 
From: "Rob Atkinson" <>
To: <>
Sent: Tuesday, June 14, 2011 8:50 AM
Subject: Re: [TowerTalk] BLACKENED BRAID?,

> If you have to bury the feedline, I'd ditch what you have even if it
> is not all contaminated or oxidized and replace it with a run of 1/2
> inch LDF4-50 heliax.  It is really not much more expensive if you get
> it from Davis RF--they have very competitive prices--and it will be
> years as in decades, before you'll have to deal with this problem
> again.   Also, do not fall into the trap of thinking a certain sort of
> feedline is okay because you will only be using it to carry low band
> RF.  A run of RG213 of only 100 feet can provide a surprising amount
> of loss on 1.8 MHz to a matched load--the best possible
> conditions--and a dB here and there and it starts to add up.   It is
> expecially important if you run relatively low power.  QRP operators
> have the most to lose.   A common mistake is to think that for QRP, RG
> 58 is okay, basing that on the power handling rating of the feedline
> instead of loss.  QRP operators should have the best possible
> feedline.  But that is off the topic as you may not be running
> extremely low power.  Still, if you go to one of these on-line loss
> calculators and enter some data about common coax types on low
> frequencies to a matched load and average lengths you may be surprised
> at the loss.
> 73
> Rob
> K5UJ
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